The present invention relates to the field of Fourier transform optical correlators.
U.S. Pat. No. 5,367,579 issued to Bahram Javidi and Quing Tang, incorporated by reference herein, discloses a joint transform correlator (JTC) wherein the optical path length between the input image plane and a first Fourier transform lens differs from the optical path length between the reference image plane and the first transform lens, in contrast with conventional JTCs. This enables the second Fourier transform lens to separate the desired cross-correlation signals from the undesired auto-correlation signals, owing to the production of a chirp function as described in the patent, to thereby enhance the performance and reliability of the correlator.
It is deemed desirable to simplify the design of the patented Javidi chirp function JTC, to effect cost savings, particularly for use in pattern image recognition in the commercial sector.